The present disclosure is generally directed toward a suspension system, and more specifically to a suspension system for a cargo dolly adapted to maintain a loading deck of the cargo dolly at a prescribed height as cargo is loaded onto the dolly, and subsequently, unloaded from the dolly.
The transport of perishable cargo by aircraft is well-known in the art. In this regard, such perishable cargo, which can encompass any type of product that must be maintained in a temperature-controlled environment, can only be efficiently and timely delivered by aircraft in many parts of the world. In fact, shipping via air may be the only viable option of transporting many types of perishable goods. Exemplary of such type of goods include fresh produce, seafood, meat products, blood and a variety of other temperature-sensitive medications, such as vaccines and the like. Perishable cargo will also encompass many other types of products well-known to those skilled in the art.
While in some cases, the duration that perishable cargo must go without being refrigerated (or heated) is of so short duration as to not affect the cargo, in many other instances perishable cargo will go for sufficient lengths of time from when delivered in a refrigerated condition at the airport to when the cargo is actually loaded on a plane. In this latter scenario, failure to continue providing adequate environmental control will cause the cargo to start spoiling, completely spoil, or otherwise become unusable for its intended purpose. Such phenomena occur very frequently with respect to food items and other heat sensitive materials such as blood and other biological/pharmaceutical products. The frequency that such damage occurs is also substantially high in areas having extremely hot climates as occurs in major cities in the states of Arizona, Nevada, New Mexico, and Texas during the summer months. Numerous other cities throughout the world likewise experience such extreme temperatures.
In practice, perishable cargo is typically containerized at refrigerated terminals and held in refrigeration until the same is transported to airlines, typically via refrigerated roller floor trucks, prior to flight time. As soon as such trucks are unloaded at the designated terminal at the airport, airline containers containing perishable cargo are first weighed and then placed into open container transport dollies for transport to the aircraft. At such point in the shipping process, however, the perishable cargo is no longer maintained in a temperature-controlled environment. As is well-known to those skilled in the art, such point in the transport of such cargo is referred to as a breaking in the “cool chain” where the perishable cargo is vulnerable to the temperatures of the external environment. During such time, the airline containers containing such perishable cargo will sit upon such open transport dollies, in some cases for up to four or more hours, and often times will be exposed to direct sunlight and extreme temperatures before ultimately being loaded into an aircraft for departure.
Such interval makes the perishable cargo especially vulnerable and it is during such time that substantial damage can occur by virtue of being exposed to a non-temperature controlled environment. In this regard, from the time that the temperature-controlled cargo is delivered to the airport and ultimately loaded on a plane, where the cargo is kept out of direct sunlight and at least protected to some extent by air conditioning, presents a significant risk that often times causes irreparable damage to the cargo resulting in substantial financial losses and property destruction.
These same issues also arise with respect to perishable air cargo being unloaded from aircraft. As discussed above, such interval from when the perishable cargo is unloaded from the aircraft to the time from when the same is ultimately stored in a temperature-controlled environment places such perishable cargo at substantial risk.
In addition to the foregoing problems associated with the potential spoilage of perishable air cargo resulting from a break in the “cool chain” is the additional vulnerability that such cargo can be tampered with, damaged, lost or even stolen. In this regard, many complications can and often do arise with respect to the transport of cargo to and from storage facilities to aircraft that, given the open nature by which perishable/high value cargo is transported, present numerous opportunities where such unfortunate events can occur. Indeed, the risk for perishable/high value cargo to become lost, damaged or stolen is exceptionally high at major airports that are very large and encounter heavy volumes of air traffic.
In fact, such vulnerability may even be deemed to pose a potential threat to safety and even national security. With respect to the former, it is well-known that the importation of numerous types of perishable cargo, and in particular agricultural products, can (or must) be inspected to insure that the same is not contaminated, whether by parasites, insects or any other type of contamination. In addition or, alternatively, the open nature by which air cargo is typically transported presents an opportunity that the same will go unchecked and thus exposes a vulnerability that the cargo can be detrimentally manipulated.
In view of the foregoing, Tofco Industries, Inc., Assignee of the present application, has developed a temperature controlled cargo transport dolly for use in transporting perishable/high value cargo to and from an aircraft. Exemplary of such apparatus is disclosed in U.S. Pat. No. 7,043,932, entitled Temperature Controlled Air Cargo Container Transport Dolly, the contents of which are expressly incorporated herein by reference. The temperature controlled cargo transport dolly includes a housing having an enclosure, and a temperature control unit attached to the housing and adapted to control the temperature within the enclosure.
Although the previously designed temperature controlled cargo transport dolly addressed many of the then-existing deficiencies associated with conventional transport containers or dollies by incorporating a temperature control unit into the dolly, there are certain limitations associated therewith. For instance, the dolly is generally operated at slow speeds to mitigate shock-related damage to the temperature control unit, as well as to the cargo being transported within the dolly. Along these lines, previous temperature controlled transport dollies typically do not include suspensions because a conventional suspension would result in a varying height of the dolly cargo deck, e.g., a heavier load would cause the deck to lower, while a lighter load would cause the deck to rise. In many instances, the dollies are used with loading docks that have a universal height requirement, such as around 20.5 inches in the air cargo industry. Thus, a dolly having a variable deck height would be difficult to use with a fixed, universal loading dock height.
Therefore, there is a substantial need in the art for temperature controlled cargo dolly having suspension capabilities, while at the same time being capable of maintaining a prescribed height of a dolly loading deck. Various aspects of the present disclosure address this particular need, as will be discussed in more detail below.